Field of the Disclosure
Embodiments relate to an organic light emitting display device and a method for driving the same, for example, to an organic light emitting display device which enables compensating the degradation of an organic light emitting diode, and a method for driving the same.
Discussion of the Related Art
According to recent developments in multimedia, there is increasing demand for flat panel displays. To satisfy this increasing demand, various flat panel displays such as liquid crystal display devices, plasma display panels, field emission display devices and organic light emitting display devices are used in practice. Among the various flat panel displays, the organic light emitting display device has been attractive as a next-generation flat panel display owing to advantages of rapid response speed and low power consumption. In addition, the organic light emitting display can emit light by itself, whereby the organic light emitting display does not have the problems associated with a narrow viewing angle.
Generally, the organic light emitting display device may include a display panel having a plurality of pixels, and a panel driver for driving the respective pixels so as to make the respective pixels emit light. In this case, the pixels may be respectively formed in pixel regions, wherein the pixel regions may be defined by the crossing of a plurality of gate lines and a plurality of data lines.
With reference to FIG. 1, each pixel may include a switching transistor (Tsw), a driving transistor (Tdr), a capacitor (Cst), and an organic light emitting diode (OLED).
As the switching transistor (Tsw) is switched on by a gate signal (GS) supplied to a gate line (GL), a data voltage (Vdata) supplied to a data line (DL) may be supplied to the driving transistor (Tdr).
As the driving transistor (Tdr) is switched by the data voltage (Vdata) supplied from the switching transistor (Tsw), it is possible to control a data current (Ioled) flowing to the organic light emitting diode (OLED) by a driving voltage (VDD) (e.g., a first power supply voltage).
The capacitor (Cst) may be connected between gate and source terminals of the driving transistor (Tdr), wherein the capacitor (Cst) may store a voltage corresponding to the data voltage (Vdata) supplied to the gate terminal of the driving transistor (Tdr), and may turn on the driving transistor (Tdr) by the use of this stored voltage.
The organic light emitting diode (OLED) may be electrically connected between the source terminal of the driving transistor (Tdr) and a cathode electrode supplied with a cathode voltage (VSS) (e.g., a second power supply voltage), wherein the organic light emitting diode (OLED) may emit light by the flow of data current (Ioled) supplied from the driving transistor (Tdr).
Each pixel of the organic light emitting display device according to the related art may control an intensity of the data current (Ioled) flowing to the organic light emitting diode (OLED) by the driving voltage (VDD) through the use of switching of the driving transistor (Tdr) according to the data voltage (Vdata), whereby the organic light emitting diode (OLED) emits light and thereby displays an image.
FIG. 2 is a graph illustrating luminance change in accordance with driving time of the organic light emitting diode (OLED) according to the related art.
As shown in FIG. 2, the organic light emitting diode (OLED) may degrade as driving time increases, which gradually deteriorates the luminance characteristics. Thus, the organic light emitting display device according to the related art may have problems of lowered luminance and luminance deviation due to the degradation of the organic light emitting diode (OLED).